Suction motor for vacuum cleaner

ABSTRACT

A cleaner ( 1 ) has a DC brushless motor ( 15 ) with stator ( 203 ) and rotor ( 212 ). Stator is mounted on a shaft and rotor is mounted inside and to a tubular body ( 207 ) about stator ( 203 ). Impeller ( 17 ) is mounted to and outside tubular body ( 207 ). The motor ( 15 ) and impeller ( 17 ) are mounted in a housing having an intake ( 17 ) and an exhaust ( 9 ). Operation of the motor and rotation of the impeller causes a partial vacuum at the intake ( 7 ) to draw air. The air is exhausted through the exhaust ( 9 ). A filter ( 61 ) prevents particles from entering the motor ( 15 ). Particles are collected in a receptacle ( 5 ) prior to the filter ( 61 ). The impeller ( 17 ) may be a squirrel cage fan, bladed fan, or centrifugal fan. A secondary exhaust ( 11 ) expels particles from the filter ( 61 ) and/or receptacle ( 5 ) by rotation of the impeller ( 17 ) in an opposite direction or by the use of a secondary DC motor and impeller. The housing ( 2 ) can fit in a cavity between conventional wall studs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.Provisional Patent Application No. 60/363,351 filed 12 Mar. 2002 by thesame inventors as listed in this application and entitled SUCTION DEVICEFOR VACUUM CLEANER. This is the specific reference to the provisionalapplication that is required under 35 U.S.C. 119(e).

It also claims priority from the above application.

TECHNICAL FIELD

The invention relates to cleaning apparatuses. More particularly, theinvention relates to cleaning apparatuses using air as the transitmechanism.

BACKGROUND ART

Cleaning apparatuses typically operate by using a partial vacuum to drawair and particles suspended in the air, such as dirt, into the cleanerwhere the particles are separated from the air. Vacuum is created usingan AC motor that turns a shaft attached to an impeller. As the shaftspins the impeller rotates and draws air into the cleaner and exhauststhe air from the cleaner.

For a central vacuum cleaning system the AC motor and impeller sitwithin a canister that is mounted in a room of a house or otherstructure. As the motor rotates the impeller, particles are collectedwithin the canister. To remove the particles, the canister is opened anda portion of the canister is removed and dumped upside.

Typically the canister is mounted in the basement or another out of theway place, as the canister can be noisy, dirty and unsightly. Thecanister must remain easily accessible for emptying.

Upright vacuum cleaners operate in a similar manner; however, thecleaner is portable.

The owner of the central vacuum cleaning system or upright cleaner mustcheck periodically to see if the canister requires emptying.

Alternative upright vacuum cleaners or central vacuum cleaning systemsare desirable.

DISCLOSURE OF THE INVENTION

In a first aspect the invention provides a suction device for use in acleaning apparatus that moves air. The device includes a casing thatdefines a substantially cylindrical cavity and the casing has first andsecond opposing ends and a first axis. The first end has an intake, andthe second end has an exhaust. A DC brushless motor is contained withinthe cavity. The motor has a stator mounted to a shaft and the motor hasa substantially cylindrical rotor mounted for rotation about the shaft.The shaft has a second axis and the shaft is fixedly mounted within thecasing with the first and second axes aligned. An impeller is fixedlymounted for rotation with the rotor. The rotation of the impeller in afirst direction causes air to be drawn through the intake and expelledthrough the exhaust.

The impeller may be mounted between the rotor and the casing. Theimpeller may be mounted about a reduced diameter portion of the rotor.The rotor may have an adaptor extending from one end, and the adaptormay have a reduced diameter from the remainder of the rotor. The reduceddiameter portion may be an adaptor that is mounted at one end of therotor. The one end of the rotor at which the adapter is mounted may becloser to the intake than the other end of the rotor.

The impeller may include a centrifugal fan. The impeller may include amulti-stage centrifugal fan.

The casing may have a diameter less than the depth of a wall stud of aconventionally framed structure. The casing may have a diameter of 5 and1/2 inches or less. The casing may have a diameter of 3 and 1/2 inchesor less.

In a second aspect the invention provides a central vacuum cleaningsystem including the above suction device and an air delivery apparatus.The casing has a diameter less than the depth of a wall stud of aconventionally framed structure, and the device is mounted within a wallcavity between wall studs of a conventionally framed house, and fluidconnection is provided between the intake and the air deliveryapparatus.

The system may have a filter between the intake and the air deliveryapparatus. The filter prevents particles from entering the intake. Thesystem may have a particle receptacle between the filter and the airdelivery apparatus. A substantial portion of the particles are releasedinto the receptacle from the air entering the intake before the airreaches the filter.

The system may have a first valve between the filter and the airdelivery apparatus and a secondary exhaust between the filter and thefirst valve, the first valve having an open position to prevent air frompassing through the first valve toward the air delivery apparatus and aclosed position to permit air to pass through the first valve from theair delivery apparatus. The secondary exhaust is for exhausting trappedparticles from the filter when the first valve is closed.

The rotation of the impeller in a second direction may cause air to bedrawn from the exhaust and to be exhausted through the secondaryexhaust. Closing of the first valve and opening of the secondary exhaustmay cause air drawn from the exhaust to be exhausted through thesecondary exhaust.

In any of the aspects, the impeller may be a set of fan bladessubstantially spaced equally about the rotor in an arc perpendicular tothe first and second axes. The impeller may be a plurality of sets offan blades, each set of fan blades substantially spaced equally aboutthe perimeter of the rotor in an arc perpendicular to the first andsecond axes, the sets positioned from one another along the first andsecond axes.

The impeller may be a plurality of staged centrifugal fans.

The impeller may be a squirrel cage fan.

In a third aspect the invention provides a cleaning system including anupright vacuum cleaner with the suction device of the first aspect as ameans for moving air through the cleaner.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show morewere clearly how it may be carried into effect, reference will now bemade, by way of example, to the accompanying drawings that show thepreferred embodiment of the present invention and in which:

FIG. 1 is a perspective view of a suction device according to thepreferred embodiment of the invention.

FIG. 2 is a perspective view of the device of FIG. 1 with its motorhousing and electronics housing removed, and a portion of its lowerportion cut-away.

FIG. 3 is a cut-away perspective view of the suction device of FIG. 1with an alternate impeller.

FIG. 4A is a longitudinal cross section of the suction device of FIG. 1.

FIG. 4B is also a longitudinal cross section of the suction device ofFIG. 1

FIG. 4C is a plan view of an alternative support plate for the suctiondevice of FIG. 1.

FIG. 4D is a longitudinal cross section of an alternative shaft profilefor the suction device of FIG. 1.

FIG. 4E is a plan view of the profile of FIG. 4D.

FIG. 4F is a plan view of a further alternate profile for the shaft ofFIG. 4D.

FIG. 4G is a plan view of another further alternate profile for theshaft of FIG. 4D.

FIG. 5 is a cross-section of the suction device of FIG. 3 showingrotation and flow patterns.

FIG. 6 is a cut-away perspective view of the suction device of FIG. 1with a squirrel cage fan impeller.

FIG. 7 is a longitudinal cross-section of the suction device of FIG. 6showing rotation and flow patterns.

FIG. 8 is a cut-away perspective view of the suction device of FIG. 1with a multi-stage centrifugal fan impeller.

FIG. 9 is a longitudinal cross-section of the suction device of FIG. 8showing rotation and flow patterns.

FIG. 10 is a cut-away perspective of the suction device of FIG. 1 with amultiple set of multiple fan blades impeller.

FIG. 11 is a longitudinal cross-section of the suction device of FIG.10.

FIG. 12 is a cross-section of a house with a central vacuuming systemusing the suction device of FIG. 10.

FIG. 13 is a cross-section of a partial wall cavity of the house of FIG.12 showing a portion of the central vacuuming system, including thesuction device of FIG. 10.

FIG. 14 is a top view cross-section of an alternative clamshell casingsuction device.

FIG. 15 is a front view of a base of the suction device of FIG. 14 witha front cover removed.

FIG. 16 is a top view cross-section of the suction device of FIG. 14with a secondary motor housing.

FIG. 17 is a front view of a base of the suction device of FIG. 16 witha front cover removed.

FIG. 18 is a front view of the suction device of FIG. 14 with an accessdoor.

FIG. 19 is a top view cross-section of an alternative external casingprofile for the suction device of FIG. 14.

FIG. 20 is cross-section of a rotor with adapter embodiment of thepresent invention.

FIG. 21 is a perspective cut-away of the suction device of FIG. 1utilizing the adapter of

FIG. 20 in a centrifugal fan embodiment.

FIG. 22 is a cross-section of the suction device of FIG. 21.

FIG. 23 is an exploded perspective view of a stage of the embodiment ofFIG. 21.

FIG. 24 is a perspective cut-away of the suction device of FIG. 1utilizing the adapter of FIG. 20 in a squirrel cage fan embodiment.

FIG. 25 is a cross-section of the suction device of FIG. 24.

FIG. 26 is a perspective cut-away of the suction device of FIG. 1utilizing the adapter of FIG. 20 in a fan blade embodiment.

FIG. 27 is a cross-section of the suction device of FIG. 26.

MODES OF CARRYING OUT THE INVENTION

For ease of understanding elements having the same reference numeralshave the same configuration and operation, except as otherwise noted.Accordingly, the description of such elements will not be repeated wheresuch configuration and operation is similar.

Referring to FIG. 1, a suction device 1 has a generally cylindricalcasing 2 that defines a substantially cylindrical cavity with vacuummotor housing 3, electronics housing 4, dirt chamber 5, dirt intake 7,primary exhaust 9, secondary exhaust 11 and mounting bracket 13.

Referring to FIG. 2, inside the motor housing 3 (which has been removedin FIG. 2) is a generally cylindrical DC brushless motor 15, and animpeller 17. The impeller 17 extends radially from the motor 15. Firstmotor support plate 19 and second motor support plate 21 are at eitherend of the housing 3. As can be seen the mounting bracket 13 can beintegrally formed with the first motor support plate 19.

The dirt chamber 5 (partially cut away) is generally tubular with aspring-loaded hinged dirt chamber door 23 enclosing one dirt chamber end25 about the dirt intake 7.

Opposing end 27 of the dirt chamber 23 opens through the first motorsupport plate 19 into the motor housing 3. The dirt chamber 23, firstmotor support plate 19 and motor housing 3 are held in a releasablesealed arrangement by bolts 29 (also visible in FIG. 1) fitted throughholes in a flange 31 of the motor housing 3 and holes in the first motorsupport plate 19 into threaded holes in a flange 33 of the dirt chamber5.

Within the electronics housing 4 are two printed circuit boards 35 thatcontain control circuitry 37 for the motor 15. The boards 35 are heldfixed in the air stream of the suction device 1 to provide cooling;while at the same time, thye boards 35 are positioned to restrict airflow minimally. The boards 35 could be externally mounted.

The impeller 17 has a first set 39 of three fan blades 41 a, 41 b and 41c equally spaced about the circumference of the motor 15 and extendingradially from the motor 15, and a second similar set 43 of three fanblades (only two of which, 45 a and 45 b are evident in FIG. 2). Theblades of the set 39 are offset from the set 43 to create the effect ofa single longer blade between adjacent blades for example 41a, 45a indifferent sets 39, 43. The sets 39 and 43 can be integrally formed orthey may be separately formed and bonded together. The number of blades41, 45 and sets 39; 43 will depend upon the particular specificationsrequired for a particular application.

Referring to FIG. 1 and FIG. 3, the motor housing 3 and electronicshousing 4 are generally tubular. The motor housing 3 opens at one end 47through the first motor support plate 19 to the dirt chamber 5. At anopposing end 49 the housing 3 opens through the second motor supportplate 21 to one open end 51 of the electronics housing 4. Opposing end53 of the electronics housing 4 is enclosed except at the primaryexhaust 9 and to provide connection, not shown, for external power andfor controls and indicators on the outside of the casing 2.

The support plates 19, 21 have a wheel 22 a and spoke 22 bconfiguration. Openings 23 c in the plates 19, 21 permit fluidconnection between the dirt chamber 5 and the motor housing 3 andbetween the motor housing 3 and the electronics housing 4, respectively.As will be evident to those in the art, there are many other possibleconfigurations to contain the motor 15 and impeller 17 and to hold inplace the shaft 201 while permitting fluid connection between the intake7 and the exhaust 9. Each such configuration falls within the principlesdescribed herein.

The electronics housing 4 steps in from the diameter of the motorhousing 3 at step 54. This allows connection of the housing 4 via boltsthrough the step 54 and holes in the second support plate 21 intothreaded holes in the housing 3. This maintains the housing 3 and 4 insealed arrangement and maintains the second support plate in a fixedrelationship with the housings 3 and 4.

Referring to FIG. 3, impeller 55 has a single set 57 of numerous fanblades 59.

A filter 61 resides within the dirt chamber 5 to prevent dirt fromentering the motor housing 3. The dirt chamber 5 acts as a receptacle 63to contain dirt that enters from the intake 7.

Referring to FIG. 4A, the motor 15 is generally cylindrical and has ashaft 201 along its longitudinal axis. A stator 203 is mounted to theshaft 201 along the longitudinal axis. The stator 203 has a core 204with windings 205 that are connected to the control circuitry 37 on theprinted circuit boards 35. The control circuitry 37 accepts mains powerof 110-230 volts AC or greater and provides DC voltage to the motor 15(see mans power cord 206, FIG. 1).

The motor 15 has a generally tubular body 207 about the stator 203. Thebody 207 will typically be formed from steel for durability; however,other materials may be used. The body 207 is enclosed at either end bycircular caps 209 that have a central cavity 211 into which are insertedring bearings 213. This permits the body 207 to rotate about the shaft201.

On the interior of the body 207 is a set of longitudinal permanentmagnets 215 of alternating poles formed in a tube 216. The tube 216rotates with the body 207. The shaft 201 is held by the first motorsupport 19 and second motor support 21 in fixed relationship with themotor housing 3.

The motor body 207 is caused to rotate by energizing sequentially thewindings 205 of the stator 203 with DC voltages of alternating phases tocause some of the windings 205 to attract one pole of the magnets 215then, as that pole of magnets 215 passes the attracting windings 205, torepel that pole of magnets 215. The structure and operation of a DCbrushless motor similar to that described herein is described in U.S.Pat. Nos. 6,206,181 B1 and 5,918,728 of Charles D. Syverson issued Mar.27, 2001 and Jul. 6, 1999 under titles Gearless Motorized ConveyorRoller and Gearless Motorized Roller With Variable Frequency Controller,respectively. Many different configurations of core 204, windings 205,phases, timing and other design elements of DC brushless motors ingeneral are known. The particular configuration of the DC brushlessmotor 15 will be a matter of design choice to fulfil the principlesoutlined herein.

The body 207 and the magnets 215 form a rotor 212 of the motor 15. Inaddition to the configuration of rotor 212 around stator 203, DCbrushless motor 15 has a number of advantages over traditional ACmotors. The motor 15 can be very efficient, up to 92% or more efficientversus approximately 40% efficiency for a traditional AC motor. There isno carbon contamination from brushes. The motor 15 can be very small,down to approximately an inch in diameter. The motor 15 can be quietwhen compared to an AC motor. Less maintenance will generally berequired.

The timing, and polarity and quantity of the voltage, of the energizingof the windings 205 is controlled by the control circuitry 37. Thetiming of the energizing of the windings 205 will also determine thedirection of rotation of the body 207. A sensor 217, for example a Halleffect sensor, may be used to determine the speed of the rotation of thebody 207 for control purposes.

It is expected that for most design configurations the motor 15 will beoperated in a range between 10,000 and 25,000 rpm, typically over 15,000rpm, to provide sufficient suction for central vacuum systemapplications. Suction for vacuum cleaner suction devices is typicallymeasured in terms of water lift. 2″ to 3.9″ of water lift is sufficientfor most vacuum cleaner applications for which the suction device 1 isintended.

Referring to FIG. 4B, certain elements of the motor 15 are shown ingreater detail. Ends 301, 303 of shaft 201 are threaded. An annularlocking base 305, 307 is provided for each end 301, 303, respectively.The bases 305, 307 are fixed to the shaft 201 and position the shaftbetween support plates 21, 19. Locking nut/washer combinations 309, 311are threaded onto each end 301, 303, respectively, to fix the shaft 201to the motor mounts 21, 19.

Referring to FIGS. 4C-4G, an alternative means of fixing the shaft 201to the support plates 21, 19 is shown. Referring to FIG. 4C, supportplate 19 and support plate 21, not shown, are provided with non-circularopening 320. In the configuration shown, the opening 320 is square.Referring to FIGS. 4D-4F, the shaft 201 has a central profile 322between the ends 301, 303 and end profile 324 at the ends 301, 303. Thecentral profile 322 is larger than the end profile 324 at least in somelocations about the circumference. Examples of practical profilesinclude square end profile 324 and circular central profile 322 (FIG.4E), square end profile 324 and larger square central profile 322 (FIG.4F), and gear tooth end profile 324 and circular central profile 322(FIG. 4G).

The non-circular end profile 324 corresponds to the non-circular opening320 in the support plates 19, 21. This fixes the shaft 201 againstrotation with respect to the housing 3.

The larger central profile 322 provides a shoulder 330 that restsagainst the support plates 19, 21 and olds the central profile 322 ofthe shaft 201 between the plates 19, 21.

Referring again to FIG. 4D, a cotter pin 340 fitted through a bore 342in the end profile 322 is used to further fix lateral movement of theshaft with respect to the plates 19, 21. Many other lateral fixing meansare possible, such as a threaded third profile and locking nut, notshown, at the outside ends of the shaft 201.

Referring again to FIG. 4B connection between the armature coils 205 andthe control circuitry 37 is by way of leads 350 fed through opening 352to a hollow, not shown, in shaft 201. Impeller blades 354 represent ageneric rotating axial flow multiple stage impeller. Other impellers arefurther described described elsewhere in this specification.

When the impeller blades 354 are rotated in one direction, inlet air(arrows A) is drawn through the impeller 354 and exhaust air (arrows B)is expelled from the impeller 354.

Referring to FIG. 5, as the motor 15 rotates in one direction (arrows A)the impeller 55 rotates with it. A partial vacuum is created in the dirtchamber 5 and the door 23 opens to draw air (arrows B) from the intake7. The air is exhausted through the primary exhaust 9.

Referring to FIG. 6, impeller 401 is a squirrel cage fan 403 with atubular center portion 405 and a plurality of longitudal blades 407punched out on three sides from the center portion 405 and angled awayfrom the motor 15. One end of the fan 403 has a cap 409 to provide thenecessary air flow path. It may also be necessary to direct air flow tothe inside of the fan 403 to create proper air flow.

Referring to FIG. 7, the blades 407 pull air (arrows B) from near themotor housing 3 into the fan 403 toward the motor 15 when the fan 403 isrotated one direction (arrows A).

Referring to FIG. 8, impeller 701 is a multi-stageseries of centrifugalfans 705 a, 705 b, 705 c having fan blades, for example blade 707. Thedesign of multi-stage centrifugal fan blades is well known. Eachsuccessive stage is thinner than the previous stage to create anincrease in suction through the stages.

Referring to FIG. 9, as the impeller 701 spins (arrows A) so that theblades 707 cut into the air (arrows B), air is drawn from the intake 7through the stages of the impeller 701 and expelled through the primaryexhaust 9.

Referring to FIG. 10, extending the impeller 55 if FIG. 3, impeller 901is made up of a large number of sets, for example set 903. Each set 903has a large number of fan blades, for example blades 905.

Referring to FIG. 11, as the impeller spins 901 in one direction (arrowsA) air (arrows B) is again drawn from the intake 7 through the impeller901 and expelled through the primary exhaust 9.

Referring generally to the Figs., there is a close spacing between theimpellers 17, 55, 401, 701, 901 and the casing 2, perhaps a fewthousands of an inch. This promotes efficiency in drawing air throughthe motor 15.

As has been described, the impellers 17, 55, 401, 701, 901 areordinarily caused by the control circuitry 37 to rotate in a directiongo as to draw air through the intake 7 and expel it through the exhaust9. It is possible to use the control circuitry 37 to cause the impellers17, 55, 401, 701, 901 to rotate in the opposite direction, in “emptymode”. This will cause air to be drawn in through the primary exhaust 9and to be expelled through the secondary exhaust 11, while closing thedoor 23. This cleans any filters and empties the dirt chamber 5.

A sensor, not shown, can be provided in the dirt chamber 5 and connectedto the control circuitry 37. The sensor can indicate to a user a levelof dirt where the device 1 should be placed in “empty mode”.Alternatively, the device 1 can be automatically placed in “empty mode”by the control circuitry 37 when the device 1 is next turned off for agiven period of time, for example three minutes or more. This period oftime allows for those situation where the user may simply be movingbetween cleaning operations. When the device is in “empty mode” then thecontrol circuitry will lockout operation of the motor for normalcleaning.

A door, not shown; (similar to door 23, although acting in an oppositemanner) will be required in line with the secondary exhaust 11 toprevent the flow of air from the dirt chamber while the motor 15 isoperating so as to draw air from the intake 7 and expel it through theexhaust 9. When the motor 15 is operated so as to intake air from theexhaust 9 and expel it through the exhaust 11, the door will open. Sucha door has not been included in the device 1 as one can be placed at theend of a run where secondary exhaust 11 exits.

Another door, not shown, acting in the same manner as the door 23 mayalso be required to allow air to be drawn in through the exhaust 9 whenthe motor 15 is in “empty mode” as the exhaust 9 would ordinarily beterminated in a door, not shown, that would prevent air from enteringthrough the exhaust.

A further door, not shown, could be used to isolate the exhaust 9 fromits termination point when the motor 15 is run in “empty mode”. Afterthis door the exhaust 11 could join the remaining run of the exhaust 9.This means that the two exhausts 9, 11 can use a single termination run.This reduces vent runs and the number of vents that exit a structure.

The various doors, including door 23, act as valves to allow and preventthe flow of air. Doors such as those described herein are simple andeffective means of providing such valves. Other valve means can be usedas will be evident to those skilled in the art.

Referring to FIG. 12, the suction device 1 can be used in a centralvacuum system 1201 of a house, or other structure, 1203 for connectionto the various tubes 1205 and hoses 1207 that make up the air deliveryapparatus for the system 1201.

Referring to FIG. 13, the motor 15 can be of a very narrow diameter, forexample, the body 207 can be 1.125″ in diameter or less. This permitsthe device 1 to be small enough to fit within a cavity 1301 between twowall studs 1303 of a conventionally framed structure. For example, thedevice 1 can be less than 5 and 1/2 inches deep and 14-½″ wide to fitwithin a cavity between nominal 2 inch by 6 inch studs on 16 inchcenters, or less than 3 and ½ inches deep and 14 and 1/2 inches wide tofit within a cavity between nominal 2 inch by 4 inch studs on 16 inchcenters. Preferrably the housing 3 would have external diameter of 3″ orless. The cavity 1301 may be backed by plywood or the like 1305 topermit the device 1 to be mounted by screws or the other fastening means1307. Referring again to FIG. 12, cavity 1301 may have an access door1309.

Referring to FIGS. 14 and 15, the casing 2 could be replaced by casing1401 of a clamshell design. Casing 1401 is divided longitudinally topermit easy access to, and factory installation of, internal components,and simplified manufacturing. The casing 1401 is held together by bolts1403. Many other means could be used to hold together the casing. Forexample, on one side the casing 1401 could be held together by hinges,not shown, to allow the casing to swing open. The casing 1401 can beinjection moulded in two halves.

Circumferential positioning bosses 1405 laterally hold in place supportplates 1402. The support plates 19, 21 can be prevented from rotating bymany different means, including for example bolts 1407. Othercircumferential bosses 1409 laterally hold in place filter dividers1411. Filtration material 1413 is trapped between the filter dividers1411. The filter dividers 1411 and that part of the casing 1401 betweenthe dividers 1411 create a filter housing 1415. Other embodimentsdescribed herein could be provided with a filter housing and filtrationmaterial as the filter 61.

The circuit boards 35 can be held in place by snap fit in opposing setsof bosses 1417 extending toward the exhaust outlet 1419 form and acrossbosses 1405.

Referring to FIGS. 16 and 17, a secondary motor housing 1601 can beadded to the casing 1401. The housing 1601 contains a secondary motor1603 with impeller 1605 that operates in a similar manner to motor 15and corresponding previously described impellers to create a secondarysuction device 1607. There is an intake 1609 into the housing 1601 andan exhaust 1611 into the motor housing of the casing 1401. When it isdesired to clean out the filter material 1613 and the dirt chamber 1615,primary exhaust outlet 1617 and primary intake 1619 are closed, andsecondary intake 1609 and secondary exhaust 1621 are opened. Operationof the secondary motor 1603 draws air from the secondary intake 1609(arrow A) through exhaust 1611 (arrow B) through the filter material1613 and dirt chamber 1615 to the secondary exhaust 1621 (arrow C).Given the limited task of the secondary suction device 1607, the suctiondevice 1607 can be substantially smaller than the primary suctiondevices.

Alternatively, the motor 15 could be reversed to draw air through theprimary exhaust 1617, close the intake 1619 and expel dirt through thesecondary exhaust 1621.

Referring to FIG. 18, as a further alternative, an access door 1801could be provided to the filtration material and/or the dirt chamber formanual cleaning.

Referring to FIG. 19, casing 1901 simply illustrates that alternativeexternal profiles may be used, for example a rectangular profiles.

Referring to FIG. 20 and beyond, an adapter 2001 can be fitted to oneend of the motor body 207. For this embodiment, like reference numeralsfrom the previously described embodiments will be used for like parts.Except as otherwise set out or required in the transferring from oneembodiment to another, parts of like reference numerals are similar andthe description of those parts will not be repeated for each embodiment.Shaft 201 extends through the adapter 2001 and is held by circular caps209 having a central cavity 211 into which are inserted ring bearings213. As with earlier embodiments, this permits the body 207 (and theadapter 2001) to rotate about the shaft 201. The adapter 2001 may beintegrally formed with the body 207 or it may be separately formed andattached by a suitable mounting method, such as corresponding threads onthe adapter 2001 and the body 207, bolts, screws, welding, bayonetmount, or other technique. The adapter 2001 may be considered a part ofthe body 207 of reduced diameter.

Referring to FIGS. 21 and 22, a multi-stage centrifugal fan impeller2101 can be mounted on the adapter 2001: It should be noted that theimpeller blades (see FIGS. 21 and 23) have been removed in FIG. 22 forclarity. Components for such impeller 2101 are well known and can beeasily adapted for use with the adapter 2001. Using the adapter 2001 itmay be possible to avoid custom design of impeller 2101 for use with thesuction device 1.

It may be necessary to lengthen the vacuum motor housing 3 toaccommodate the new impeller 2101, it may also be necessary to have ahousing of greater circumference.

Referring FIG. 23, an example centrifugal fan impeller stage 2102comprises a first disk 2301 having centrifugal blades 2303 on onesurface; A second disk 2305 is attached to the first disk, such that theblades 2303 are sandwiched between the first disk 2301 and second disk2505. The blades 2303 may be integrally formed on the first disk 2301.The first disk 2303 may have pins 2307 extending beyond the blades 2303to engage the second disk and prevent the disks 2301, 2305 from rotatingwith respect to one another. The pins 2307 may extend through the seconddisk 2305 and be attached by welding or riveting (for example if thematerial is plastic, the pins 2307 could be simply melted to rivet thedisks 2301, 2305 to one another.

In use, the stage 2102 is rotated such that air is drawn in throughopening 2309 in disk 2305. The blades 2303 create a vacuum that drawsthe the stage and out the periphery of the stage 2102. Opening 2311 issealed by the adapter 2001. The disk 2303 has a slightly smallerdiameter than the disk 2305. This prevents air from being sucked arounddisk 2305, while allowing air to be expelled around the periphery ofdisk 2303.

If multiple stages 2102 are used, there must be a space for air returnbetween stages. Thus, a spacer, such as spacer 2313 may be used. Thespacer must be have a smaller diameter than the opening 2309 to ensureit does not block air flow into the stage.

Referring again to FIGS. 20 and 22, the impeller 2101 is held in fixedrotation with the body 207. The adapter 2001 has external threads 2005.The impeller 2101 is placed on the adapter 2001 and a nut 2201 isthreaded on to threads 2005 to force the impeller against the body 207.A friction fit between impeller stages 2102 is typically sufficient;however, many other means could be used to mount and hold the impellersin place, such as bolts, screws, retaining rings, locking tabs and thelike.

The operation of suction device 1 with adapter 2001 and impeller 2101 isotherwise similar to the embodiments previously described.

Referring to FIGS. 24 and 25, a squirrel cage fan impeller 2401embodiment for use with adapter 2001 is shown. The structural andoperation of the impeller 2401 embodiment is evident from thedescription of the descriptions of the previous embodiments, inparticular the embodiments of FIGS. 6 and 7 when read in conjunctionwith the description of FIGS. 20 through 22.

Similarly, referring to FIGS. 26 and 27, fan blade impeller 2601embodiment for use with adapter 2001 is shown. The structural andoperation of the impeller 2601 embodiment is evident from thedescription of the descriptions of the previous embodiments, inparticular the embodiments of FIG. 3 when read in conjunction with thedescription of FIGS. 20 through 22. A multiple stage fan blade impellerhas not been shown; however, its structure and operation is evident fromthe description of the previous embodiments, in particular theembodiments of FIG. 10 when read in light of the description of FIGS. 20through 22 and FIGS. 26 and 27.

The impellers 2001 and 2401 are best mounted on the intake side of themotor 15 in order to reduce blockage of intake air to the impeller 2001,2401, and to take advantage of the impellers 2001, 2401 expelling air attheir periphery where it will not be blocked by the motor 15.

As with other embodiments, the casings 2, 1401 or 1901 can be adapted toprovide channelling of the air flow within and between stages of theimpellers described herein.

It will be understood by those skilled in the art that this descriptionis made with reference to the preferred embodiment and that it ispossible to make other embodiments employing the principles of theinvention which fall within its spirit and scope as defined by thefollowing claims.

As an example, the suction device 1 has been described generally withapplication to central vacuuming systems. The device 1 is equallyapplicable to upright vacuum cleaner applications for moving air throughan upright vacuum cleaner. As such applications are portable, a designermay not wish to use the “empty mode” features, and may wish to use atraditional vacuum cleaner bag in the dirt chamber to capture the dirt.Access would then have to be provided for the user to the bag as isknown in the art.

Similarly, the “empty mode” features are not required for central vacuumsystem applications. A traditional removable canister could be used fora portion of the dirt chamber 5 with an intake 7 and door 23 on thetubular portion of the dirt chamber 5 above the removable canister.

Even where a removable canister is not used, the intake 7 and door 23could be placed on the tubular portion of the dirt chamber 5. This mayprevent dirt from fouling the operation of the door 23. This may requireextra care to ensure that the door 23 remains shut during “empty mode”.

1. A suction device for use in a cleaning apparatus that moves air, thedevice comprising: a) A casing defining a substantially cylindricalcavity, the casing having first and end opposing ends and a first axis,the first end having an intake, and the second end having an exhaust, b)A DC brushless motor contained within the cavity, the motor having astator mounted to a shaft and the motor having a substantiallycylindrical rotor mounted for rotation about the shaft, the shaft havinga second axis and the shaft being fixedly mounted within the casing withthe first and second axes aligned, and c) An impeller fixedly mountedfor rotation with the rotor, wherein rotation of the impeller in a firstdirection causes air to be drawn through the intake and expelled throughthe exhaust.
 2. The suction device on claim 1, wherein the impeller ismounted between the rotor and the casing.
 3. The suction device of claim1, wherein the impeller is mounted about a reduced diameter portion ofthe rotor.
 4. The suction device of claim 1, wherein the rotor has anadaptor extending from one end, and the adaptor has a reduced diameterfrom the remainder of the rotor.
 5. The suction device of claim 3,wherein the reduced diameter portion is an adaptor that is mounted atone end of the rotor.
 6. The suction device of claim 5, wherein the oneend of the rotor at which the adapter is mounted is closer to the intakethan the other end of the rotor.
 7. The suction device of claim 3,wherein the impeller comprises a centrifugal fan.
 8. The suction deviceof claim 3, wherein the impeller comprises a multi-stage centrifugalfan.
 9. The suction device of claim 1, wherein the casing has a diameterless than the depth of a wall stud of a conventionally framed structure.10. The suction device of claim 1, wherein the casing has a diameter of5 and 1/2 inches or less.
 11. The suction device of claim 1, wherein thecasing has a diameter of 3 and 1/2 inches or less.
 12. A central vacuumcleaning system comprising the suction device of claim 1 and an airdelivery apparatus, wherein the casing has a diameter less than thedepth of a wall stud of a conventionally framed structure, and thedevice is mounted within a wall cavity between wall studs of aconventionally framed house, and air connection is provided between theintake and the air delivery apparatus.
 13. The system of claim 12,further comprising a filter between the intake and the air deliveryapparatus, wherein the filter prevents particles from entering theintake.
 14. The system of claim 13, further comprising a particlereceptacle between the filter and the air delivery apparatus, wherein asubstantial portion of the particles are released into the receptaclefrom the air entering the intake before the air reaches the filter. 15.The system of claim 14, further comprising a first valve between thefilter and the air delivery apparatus and a secondary exhaust betweenthe filter and the first valve, the first valve having an open positionto prevent air from passing through the first valve toward the airdelivery apparatus and a closed position to permit air to pass throughthe first valve from the air delivery apparatus, the secondary exhaustfor exhausting trapped particles from the filter when the first valve isclosed.
 16. The system of claim 15, wherein the rotation of the impellerin a second direction causes air to be drawn from the exhaust and to beexhausted through the secondary exhaust.
 17. The system of claim 16,wherein closing of the first valve and opening of the secondary exhaustcauses air drawn from the exhaust to be exhausted through the secondaryexhaust.
 18. The device of claim 1, wherein the impeller is a set of fanblades substantially spaced equally about the rotor in an arcperpendicular to the first and second axes.
 19. The device of claim 1,wherein the impeller is a plurality of sets of fan blades, each set offan blades substantially spaced equally about the rotor in an arcperpendicular to the first and second axes, the sets positioned from oneanother along the first and second axes.
 20. The device of claim 1,wherein the impeller is a plurality of centrifugal fans.
 21. The deviceof claim 1, wherein the impeller is a squirrel cage fan.
 22. A cleaningsystem comprising an upright vacuum cleaner with the suction device ofclaim 1 as a means for moving air through the cleaner.
 23. A centralvacuum cleaning system comprising the suction device of claim 1 and anair delivery apparatus, and air connection is provided between theintake and the air delivery apparatus.
 24. The system of claim 23,further comprising a filter between the intake and the air deliveryapparatus, wherein the filter prevents particles from entering theintake.
 25. The system of claim 24, further comprising a particlereceptacle between the filter and the air delivery apparatus, wherein asubstantial portion of the particles are released into the receptaclefrom the air entering the intake before the air reaches the filter. 26.The system of claim 25, further comprising a first valve between thefilter and the air delivery apparatus and a secondary exhaust betweenthe filter and the first valve, the first valve having an open positionto prevent air from passing through the first valve toward the airdelivery apparatus and a closed position to permit air to pass throughthe first valve from the air delivery apparatus, the secondary exhaustfor exhausting trapped particles from the filter when the first valve isclosed.
 27. The system of claim 26, wherein the rotation of the impellerin a second direction causes air to be drawn from the exhaust and to beexhausted through the secondary exhaust.
 28. The system of claim 27,wherein closing of the first valve and opening of the secondary exhaustcauses air drawn from the exhaust to be exhausted through the secondaryexhaust.